Do Heat Waves Spur Violence?

Are the triple digit temperatures provoking people to do their worst?

By Jef Akst | July 25, 2011

FLICKR, MIKE NELSON

Hot weather has long been linked to violence, but whether or not it is the cause of our species’ bad temperedness remains unclear. In fact, a study conducted at the turn of the 21st century suggested that at around 80 degrees Fahrenheit, assault rates no longer increased with temperature, but actually started to drop. This led some researchers to suggest that perhaps moderate levels of heat, and thus discomfort, provoke aggression, while extreme heat and discomfort made people want to flee, Wired Science reports. Another theory holds that because many displays of violence depend on social opportunity—as the weather increases, and people spend more time outdoors, violent crime rises, but as the temperatures become too hot to handle, and people retreat indoors, the trend stops.

But reanalyzing the data in 2005, Iowa State University psychologist Craig Anderson found that the trend of increased violence with rising temperatures continued even past 80 degrees, if he took account the time of day. Specifically, most assaults occurred between 9 pm and 3 am, when temperatures are generally cooler. And within this time period, Anderson found that higher temperatures indeed led to more assault cases. This interpretation of the data supports physiological hypotheses, such as the increases in heart rate, blood circulation and sweating, as well as metabolic changes, associated with hot weather could alter the activity of the sympathetic nervous system, which may in turn influence a person’s likelihood of escalating a situation or walking away from it. Heat is also known to increase testosterone production, which can promote aggression.

Other hypotheses draw on the notion that physical discomfort has been associated with negative memories, which could alter a person’s reactions towards hostility. Indeed, some studies have shown that overheated people struggle with rational thinking, and hot weather can cause people to interpret neutral situations as hostile or violent. Though these explanations are still entirely speculative, Anderson thinks there may be a real biological explanation for the association found between heat and violence.

Studies conducted have shown that increasing the temperature reduces the respiratory activity of man. Motor activity is also reduced.Â Increased accumulation of moisture in the body, with an increase in perspiration, makes a person aggressive.

Studies conducted have shown that increasing the temperature reduces the respiratory activity of man. Motor activity is also reduced.Â Increased accumulation of moisture in the body, with an increase in perspiration, makes a person aggressive.

I'm surprised alcohol was not mentioned as a contributing factor."Specifically, most assaults occurred between 9 pm and 3 am... within this time period, Anderson found that higher temperatures indeed led to more assault cases."This time period sounds like "prime drinking time" for younger people. When it gets hotter, people get "thirstier" and drink more alcohol, which can lead to more agressive behaviour.Of course, I don't have real evidence to support this claim, but alcohol consumption seems a simpler explanation than getting into hard-to-measure physiological changes.A simple test would be to look at the increase in the number of assaults where alcohol was a factor, and where it was not.Â If both numbers change at the same rate vs. temperature, then alcohol is probably not a factor; but if the increase in assaults is greater for alcohol-related incidents, then alcohol is likely a strong factor.Has this been done?

Studies conducted have shown that increasing the temperature reduces the respiratory activity of man. Motor activity is also reduced.Â Increased accumulation of moisture in the body, with an increase in perspiration, makes a person aggressive.

I'm surprised alcohol was not mentioned as a contributing factor."Specifically, most assaults occurred between 9 pm and 3 am... within this time period, Anderson found that higher temperatures indeed led to more assault cases."This time period sounds like "prime drinking time" for younger people. When it gets hotter, people get "thirstier" and drink more alcohol, which can lead to more agressive behaviour.Of course, I don't have real evidence to support this claim, but alcohol consumption seems a simpler explanation than getting into hard-to-measure physiological changes.A simple test would be to look at the increase in the number of assaults where alcohol was a factor, and where it was not.Â If both numbers change at the same rate vs. temperature, then alcohol is probably not a factor; but if the increase in assaults is greater for alcohol-related incidents, then alcohol is likely a strong factor.Has this been done?

I'm surprised alcohol was not mentioned as a contributing factor."Specifically, most assaults occurred between 9 pm and 3 am... within this time period, Anderson found that higher temperatures indeed led to more assault cases."This time period sounds like "prime drinking time" for younger people. When it gets hotter, people get "thirstier" and drink more alcohol, which can lead to more agressive behaviour.Of course, I don't have real evidence to support this claim, but alcohol consumption seems a simpler explanation than getting into hard-to-measure physiological changes.A simple test would be to look at the increase in the number of assaults where alcohol was a factor, and where it was not.Â If both numbers change at the same rate vs. temperature, then alcohol is probably not a factor; but if the increase in assaults is greater for alcohol-related incidents, then alcohol is likely a strong factor.Has this been done?

Alcohol, in Arabic - supporting life. Alcohol disinhibited mind and man shows his true colors.Â Increased temperature reduces the activity, alcohol at a high temperature slows down the motor activity. If you want to verify this? Drink a glass of alcohol.Â Put on a warm coat. Run five or ten miles. Then you will not be able to write like that.Â Wear a warm coat. Run 5 kilometers. Then you do not want to write like that.

Â @Physiology expert:I'm not sure of the point you are trying to make.This is not an experiment being conducted to test a hypothesis, this is an epidemiological study trying to explain an observed phenomenon.I'm not referring to having ONE alcoholic drink, or doing any sort of intense physical activity, or performing cognitive tasks such as writing.The people I'm referring to are having several (6+) drinks in a night, and generally standing around or dancing (in a way that is not exerting a lot of energy).These people suffer only from cognitive impairment and loss of co-ordination.Â They can still walk, run, and punch.Drunk people can get very aggressive and dangerous.Â Talk to any police officer that works in a college town; talk to the security staff at bars & night clubs; talk to college students who go to bars & night clubs.Â They will have stories to tell.

I'm not saying that it is only heat, or only alcohol that increases the aggressive behaviour, but there is enough anecdotal evidence that alcohol should have been considered as a POTENTIAL contributing factor to this phenomenon.I think Dr. Anderson should have also looked at alcohol in his re-analysis, or if it has been investigated before, it should have been mentioned in the article whether alcohol is known to have an effect or not.

Â @Physiology expert:I'm not sure of the point you are trying to make.This is not an experiment being conducted to test a hypothesis, this is an epidemiological study trying to explain an observed phenomenon.I'm not referring to having ONE alcoholic drink, or doing any sort of intense physical activity, or performing cognitive tasks such as writing.The people I'm referring to are having several (6+) drinks in a night, and generally standing around or dancing (in a way that is not exerting a lot of energy).These people suffer only from cognitive impairment and loss of co-ordination.Â They can still walk, run, and punch.Drunk people can get very aggressive and dangerous.Â Talk to any police officer that works in a college town; talk to the security staff at bars & night clubs; talk to college students who go to bars & night clubs.Â They will have stories to tell.

I'm not saying that it is only heat, or only alcohol that increases the aggressive behaviour, but there is enough anecdotal evidence that alcohol should have been considered as a POTENTIAL contributing factor to this phenomenon.I think Dr. Anderson should have also looked at alcohol in his re-analysis, or if it has been investigated before, it should have been mentioned in the article whether alcohol is known to have an effect or not.

Â @Physiology expert:I'm not sure of the point you are trying to make.This is not an experiment being conducted to test a hypothesis, this is an epidemiological study trying to explain an observed phenomenon.I'm not referring to having ONE alcoholic drink, or doing any sort of intense physical activity, or performing cognitive tasks such as writing.The people I'm referring to are having several (6+) drinks in a night, and generally standing around or dancing (in a way that is not exerting a lot of energy).These people suffer only from cognitive impairment and loss of co-ordination.Â They can still walk, run, and punch.Drunk people can get very aggressive and dangerous.Â Talk to any police officer that works in a college town; talk to the security staff at bars & night clubs; talk to college students who go to bars & night clubs.Â They will have stories to tell.

I'm not saying that it is only heat, or only alcohol that increases the aggressive behaviour, but there is enough anecdotal evidence that alcohol should have been considered as a POTENTIAL contributing factor to this phenomenon.I think Dr. Anderson should have also looked at alcohol in his re-analysis, or if it has been investigated before, it should have been mentioned in the article whether alcohol is known to have an effect or not.

Alcohol, in Arabic - supporting life. Alcohol disinhibited mind and man shows his true colors.Â Increased temperature reduces the activity, alcohol at a high temperature slows down the motor activity. If you want to verify this? Drink a glass of alcohol.Â Put on a warm coat. Run five or ten miles. Then you will not be able to write like that.Â Wear a warm coat. Run 5 kilometers. Then you do not want to write like that.

Alcohol, in Arabic - supporting life. Alcohol disinhibited mind and man shows his true colors.Â Increased temperature reduces the activity, alcohol at a high temperature slows down the motor activity. If you want to verify this? Drink a glass of alcohol.Â Put on a warm coat. Run five or ten miles. Then you will not be able to write like that.Â Wear a warm coat. Run 5 kilometers. Then you do not want to write like that.

Probably this scientist mustÂ come here toÂ Colombia (South America)Â specifically to the state of Huila and South of Tolima,Â where the weather is so hot, but the people is notÂ so violent like in another places, in this state the people is cool and lazy, even in your speech. Colombia was colonized by Spain,Â the worst people of Spain came to Colombia and thisÂ inherithanceÂ become in violence not only the weather.

Probably this scientist mustÂ come here toÂ Colombia (South America)Â specifically to the state of Huila and South of Tolima,Â where the weather is so hot, but the people is notÂ so violent like in another places, in this state the people is cool and lazy, even in your speech. Colombia was colonized by Spain,Â the worst people of Spain came to Colombia and thisÂ inherithanceÂ become in violence not only the weather.

Probably this scientist mustÂ come here toÂ Colombia (South America)Â specifically to the state of Huila and South of Tolima,Â where the weather is so hot, but the people is notÂ so violent like in another places, in this state the people is cool and lazy, even in your speech. Colombia was colonized by Spain,Â the worst people of Spain came to Colombia and thisÂ inherithanceÂ become in violence not only the weather.